Semiconductor devices and methods of fabricating the same

Abstract

A method of fabricating one or more semiconductor devices includes forming a trench in a semiconductor substrate, performing a cycling process to remove contaminants from the trench, and forming an epitaxial layer on the trench. The cycling process includes sequentially supplying a first reaction gas containing germane, hydrogen chloride and hydrogen and a second reaction gas containing hydrogen chloride and hydrogen onto the semiconductor substrate.

What is claimed is:  
     
       1. A semiconductor device comprising:
 a substrate; 
 a plurality of gate structures disposed on a top surface of the substrate, and including a first gate structure, a second gate structure and a third gate structure; 
 an isolation layer disposed in the substrate; 
 a first epitaxial layer disposed in the substrate, and disposed between the first gate structure and the second gate structure; 
 a second epitaxial layer disposed in the substrate, and disposed between the second gate structure and the third gate structure; and 
 a third epitaxial layer disposed in the substrate, and disposed between the third gate structure and the isolation layer, 
 wherein each of the first epitaxial layer and the second epitaxial layer includes a v-shaped lower portion, 
 wherein the third epitaxial layer includes an upper surface that is inclined with respect to the top surface of the substrate, 
 wherein the upper surface of the third epitaxial layer is substantially flat, and 
 wherein the upper surface of the third epitaxial layer contacts the third gate structure and the isolation layer. 
 
     
     
       2. The semiconductor device of  claim 1 , further comprising:
 a first silicide layer disposed between the first gate structure and the second gate structure, and disposed on an upper surface of the first epitaxial layer; and 
 a second silicide layer disposed between the second gate structure and the third gate structure, and disposed on an upper surface of the second epitaxial layer. 
 
     
     
       3. The semiconductor device of  claim 2 , wherein each of the first silicide layer and the second silicide layer is not formed lower than the top surface of the substrate. 
     
     
       4. The semiconductor device of  claim 2 , wherein each of the first silicide layer and the second silicide layer is formed at a level equal to or higher than the top surface of the substrate. 
     
     
       5. The semiconductor device of  claim 1 , wherein the plurality of gate structures include a fourth gate structure. 
     
     
       6. The semiconductor device of  claim 5 , further comprising a fourth epitaxial layer disposed in the substrate, and disposed between the first gate structure and the fourth gate structure. 
     
     
       7. The semiconductor device of  claim 1 , wherein each of the first epitaxial layer and the second epitaxial layer includes an upper surface that is substantially parallel with respect to the top surface of the substrate. 
     
     
       8. The semiconductor device of  claim 1 , wherein the upper surface of the third epitaxial layer contacts a side surface of the isolation layer. 
     
     
       9. The semiconductor device of  claim 1 , wherein the first epitaxial layer includes a first corner, a second corner and a third corner, the first corner protruding toward a first channel region under the first gate structure, the second corner protruding toward a second channel region under the second gate structure, and the third corner protruding downwardly to a bottom surface of the substrate. 
     
     
       10. The semiconductor device of  claim 1 ,
 wherein the first epitaxial layer has a substantially symmetrical cross-sectional profile with respect to a first imaginary vertical line crossing a center of the first epitaxial layer, and 
 wherein the second epitaxial layer has a substantially symmetrical cross-sectional profile with respect to a second imaginary vertical line crossing a center of the second epitaxial layer. 
 
     
     
       11. The semiconductor device of  claim 1 , wherein the third epitaxial layer has a non-symmetrical cross-sectional profile with respect to a third imaginary vertical line crossing a center of the third epitaxial layer. 
     
     
       12. The semiconductor device of  claim 1 , wherein a first portion of the upper surface of the third epitaxial layer is higher than a second portion of the upper surface of the third epitaxial layer, the first portion of the upper surface of the third epitaxial layer contacting the third gate structure, and the second portion of the upper surface of the third epitaxial layer contacting the isolation layer. 
     
     
       13. The semiconductor device of  claim 1 , wherein the upper surface of the third epitaxial layer that is inclined with respect to the top surface of the substrate is below the third gate structure. 
     
     
       14. The semiconductor device of  claim 1 ,
 wherein the third gate structure includes a spacer, and 
 wherein the upper surface of the third epitaxial layer contacts a lower surface of the spacer of the third gate structure. 
 
     
     
       15. A semiconductor device comprising:
 a substrate; 
 a plurality of gate structures disposed on a top surface of the substrate, and including a first gate structure, a second gate structure and a third gate structure; 
 an isolation layer disposed in the substrate; 
 a first epitaxial layer disposed in the substrate, and disposed between the first gate structure and the second gate structure; 
 a second epitaxial layer disposed in the substrate, and disposed between the second gate structure and the third gate structure; 
 a third epitaxial layer disposed in the substrate, and disposed between the third gate structure and the isolation layer; 
 a first silicide layer disposed between the first gate structure and the second gate structure, and disposed on an upper surface of the first epitaxial layer; and 
 a second silicide layer disposed between the second gate structure and the third gate structure, and disposed on an upper surface of the second epitaxial layer, 
 wherein each of the first epitaxial layer and the second epitaxial layer includes a v-shaped lower portion, 
 wherein the third epitaxial layer includes an upper surface that is inclined with respect to the top surface of the substrate, and 
 wherein each of the first silicide layer and the second silicide layer is not formed lower than the top surface of the substrate. 
 
     
     
       16. The semiconductor device of  claim 13 ,
 wherein the upper surface of the third epitaxial layer is substantially flat, and 
 wherein the upper surface of the third epitaxial layer contacts the third gate structure and the isolation layer. 
 
     
     
       17. The semiconductor device of  claim 13 , wherein each of the first silicide layer and the second silicide layer is formed at a level equal to or higher than the top surface of the substrate. 
     
     
       18. The semiconductor device of  claim 13 , wherein each of the first epitaxial layer and the second epitaxial layer includes an upper surface that is substantially parallel with respect to the top surface of the substrate. 
     
     
       19. The semiconductor device of  claim 15 , wherein a first portion of the upper surface of the third epitaxial layer is higher than a second portion of the upper surface of the third epitaxial layer, the first portion of the upper surface of the third epitaxial layer contacting the third gate structure, and the second portion of the upper surface of the third epitaxial layer contacting the isolation layer. 
     
     
       20. The semiconductor device of  claim 15 , wherein the upper surface of the third epitaxial layer that is inclined with respect to the top surface of the substrate is below the third gate structure. 
     
     
       21. The semiconductor device of  claim 15 ,
 wherein the third gate structure includes a spacer, and 
 wherein the upper surface of the third epitaxial layer contacts a lower surface of the spacer of the third gate structure. 
 
     
     
       22. A semiconductor device comprising:
 a substrate; 
 a plurality of gate structures disposed on a surface of the substrate, and including a first gate structure, a second gate structure, a third gate structure and a fourth gate structure; 
 an isolation layer disposed in the substrate; 
 a first epitaxial layer disposed in the substrate, and disposed between the first gate structure and the second gate structure; 
 a second epitaxial layer disposed in the substrate, and disposed between the second gate structure and the third gate structure; 
 a third epitaxial layer disposed in the substrate, and disposed between the third gate structure and the fourth gate structure; and 
 a fourth epitaxial layer disposed in the substrate, and disposed between the fourth gate structure and the isolation layer, 
 wherein each of the first epitaxial layer, the second epitaxial layer and the third epitaxial layer includes a v-shaped lower portion, and 
 wherein the fourth epitaxial layer includes an upper surface that is inclined with respect to the top surface of the substrate. 
 
     
     
       23. The semiconductor device of  claim 22 ,
 wherein the upper surface of the fourth epitaxial layer is substantially flat, and 
 wherein the upper surface of the fourth epitaxial layer contacts the fourth gate structure and the isolation layer. 
 
     
     
       24. The semiconductor device of  claim 18 , further comprising:
 a first silicide layer disposed between the first gate structure and the second gate structure, and disposed on an upper surface of the first epitaxial layer; and 
 a second silicide layer disposed between the second gate structure and the third gate structure, and disposed on an upper surface of the second epitaxial layer, 
 wherein each of the first silicide layer and the second silicide layer is not formed lower than the top surface of the substrate, and 
 wherein each of the first silicide layer and the second silicide layer is formed at a level equal to or higher than the top surface of the substrate. 
 
     
     
       25. The semiconductor device of  claim 22 , wherein the upper surface of the fourth epitaxial layer that is inclined with respect to the top surface of the substrate is below the fourth gate structure. 
     
     
       26. The semiconductor device of  claim 22 ,
 wherein the fourth gate structure includes a spacer, and 
 wherein the upper surface of the fourth epitaxial layer contacts a lower surface of the spacer of the fourth gate structure. 
 
     
     
       27. A semiconductor device comprising:
 a substrate; 
 a first gate structure on a top surface of the substrate; 
 a second gate structure on the top surface of the substrate and including a spacer; 
 an isolation layer in the substrate; 
 a first epitaxial layer in the substrate, and between the first gate structure and the second gate structure; and 
 a second epitaxial layer in the substrate, and between the second gate structure and the isolation layer, 
 wherein at least a portion of an upper surface of the first epitaxial layer is parallel with respect to a top surface of the substrate, 
 wherein at least a portion of an upper surface of the second epitaxial layer is inclined with respect to the top surface of the substrate and is below the second gate structure, and 
 wherein the upper surface of the second epitaxial layer contacts the second gate structure and the isolation layer wherein the first epitaxial layer has a v-shaped lower portion. 
 
     
     
       28. The semiconductor device of  claim 27 , wherein the upper surface of the second epitaxial layer contacts a lower surface of the spacer of the second gate structure. 
     
     
       29. The semiconductor device of  claim 27 , wherein upper surface of the first epitaxial layer contacts the first gate structure and the second gate structure.